Vessel prosthesis for replacing hollow organs in humans and animals and in particular blood vessels have long been known. They are generally made from textile material and in particular a knitted fabric (DE-A2-26 13 575 corresponding to U.S. Pat. No. 4,047,252, DE-A2-20 09 349 corresponding to U.S. Pat. No. 3,945,052 and DE-A1-24 61 370 corresponding to U.S. Pat. No. 3,878,565). However they can also be made from non-textile materials (EP-A1-0 106 496 and BG-A1-15 06 432). In general, the vessel prosthesis are porous, so as to permit a growing in of the tissue for obtaining conditions which are as natural as possible. However, since after the implantation of the prosthesis, these pores frequently lead to undesirably high body fluid loseses, it is desirable to seal said pores with a material resorbable by the body and which is successively replaced by the growing in tissue.
It is known from DE-A2-14 94 939 to use procollagen as the impregnating agent, which is applied to the porous prosthesis in acid solution and then rendered insoluble by increasing the pH-value.
The use of collagen for sealing is known from DE-A2-14 91 218, U.S. Pat. No. 4,167,,045, DE-A1-34 03 127 and De-A1-35 03 126. The crosslinking of collagen normally takes place with aldehydes, particularly formaldehyde.
It is also known to impregnate porous vessel prostheses with soluble gelatin and to crosslink the same (DE-A2-14 94 939), crosslinking taking place with the aid of thiol group-containing compounds with subsequent oxidative crosslinking, accompanied by the formation of disulphide bridges.
High demands are made on the characteristics of the impregnating coating, which must adhere well to the prosthesis body, provide a good sealing thereof, be ealstic and in particular not release any harmful products during resorption. The known impregnated prostheses only partly fulfil these requirements. In addition, they are far from easy to produce, or expensive starting materials are required, which is prejudicial to industrial manufacture.